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Essential Medicines List (EML) 2019 Application for the inclusion of imipenem/cilastatin, meropenem and amoxicillin/clavulanic acid in the WHO Model List of Essential Medicines, as reserve second-line drugs for the treatment of multidrug-resistant tuberculosis (complementary lists of anti-tuberculosis drugs for use in adults and children) General items 1. Summary statement of the proposal for inclusion, change or deletion This application concerns the updating of the forthcoming WHO Model List of Essential Medicines (EML) and WHO Model List of Essential Medicines for Children (EMLc) to include the following medicines: 1) Imipenem/cilastatin (Imp-Cln) to the main list but NOT the children’s list (it is already mentioned on both lists as an option in section 6.2.1 Beta Lactam medicines) 2) Meropenem (Mpm) to both the main and the children’s lists (it is already on the list as treatment for meningitis in section 6.2.1 Beta Lactam medicines) 3) Clavulanic acid to both the main and the children’s lists (it is already listed as amoxicillin/clavulanic acid (Amx-Clv), the only commercially available preparation of clavulanic acid, in section 6.2.1 Beta Lactam medicines) This application makes reference to amendments recommended in particular to section 6.2.4 Antituberculosis medicines in the latest editions of both the main EML (20th list) and the EMLc (6th list) released in 2017 (1),(2). On the basis of the most recent Guideline Development Group advising WHO on the revision of its guidelines for the treatment of multidrug- or rifampicin-resistant (MDR/RR-TB)(3), the applicant considers that the three agents concerned be viewed as essential medicines for these forms of TB in countries. In many low resource settings, patients with MDR/RR-TB and extensively drug-resistant (XDR- TB) are inadequately treated and this is often because medicines such as these are sparsely available to compose a suitable regimen(4). Imp-Cln and Mpm are collectively referred to as carbapenems and have been classified among the Group C agents at the latest update of the WHO recommendations; their action is potentiated by the co-administration of Amx-Clv. Carbapenems have been shown to be effective in reducing treatment failure and death when used in MDR-TB treatment regimens. These agents should therefore become more widely available to specialized care centres of national TB programmes and other health care providers treating M/XDR-TB patients. As the numbers of TB cases decline in the world, the global market for anti-TB drugs shrinks; second‐line medicines used to treat M/XDR-TB are destined to become less easily available. Moreover, global stock outs occur regularly. The inclusion of Imp-Cln, Mpm and Amx-Clv on the EML is one more step to increase the confidence of pharmaceutical manufacturers to invest more in production of these medicines. This request to the EML is very timely given the recent comprehensive update of WHO guidance, which attests to the importance of the three medicines in this application to strengthen treatment regimens in children and adults when other alternatives are compromised (see Table 1). It is expected to facilitate the combined efforts of national TB programmes, technical partners and funding agencies to improve the outcomes and reduce avoidable mortality for close to 600,000 new MDR/RR-TB patients estimated to develop active disease in the world each year. Table 1. Grouping of medicines recommended for use in longer MDR-TB regimens, WHO, 2018 GROUPS MEDICINE Group A Levofloxacin OR Moxifloxacin Lfx / Mfx Bedaquiline Bdq Linezolid Lzd Group B Clofazimine Cfz Cycloserine OR Terizidone Cs / Trd Group C Ethambutol E Delamanid Dlm Pyrazinamide Z Imipenem-cilastatin OR Meropenem1 Ipm-Cln / Mpm Amikacin (OR Streptomycin) Am / (S) Ethionamide OR Prothionamide Eto / Pto p-aminosalicylic acid PAS 1 Every dose of Imp-Cln and Mpm is administered with clavulanic acid, which is only available in formulations combined with amoxicillin (Amx-Clv). Amx-Clv is not counted as an additional effective TB agent and should not be used without Imp-Cln or Mpm. 2. Name of the focal point in WHO submitting or supporting the application (where relevant) The focal point is the Unit of Laboratories, Diagnostics and Drug-resistance of the Global TB Programme of WHO Headquarters (WHO/HTM/GTB/LDR). The technical personnel directly concerned are Dennis FALZON and Ernesto JARAMILLO. 3. Name of the organization(s) consulted and/or supporting the application The Global Drug Facility has been consulted. 4. International Nonproprietary Name (INN, generic name) of the medicine The WHO INN (generic name) of the medicines are Imipenem / cilastatin (5), meropenem (6), and amoxicillin and clavulanic acid (5). Technical sheets about each individual medicine are in Annex 1. 5. Formulation proposed for inclusion; including adult and paediatric (if appropriate) Medicine Anatomical Common formulations Therapeutic Chemical (ATC) Imipenem / J01DH51 Powder for injection: cilastatin 250 mg (as monohydrate) + 250 mg (as sodium salt) in vial 500 mg (as monohydrate) + 500 mg (as sodium salt) in vial Meropenem J01DH02 Powder for injection: 500 mg (anhydrous) in vial 1 g (anhydrous) in vial Amoxicillin and J01CR02 Tablet: clavulanic acid 250 mg amoxicillin (as trihydrate) + 125 mg clavulanic acid (as potassium salt) 500 mg amoxicillin (as trihydrate) + 125 mg clavulanic acid (as potassium salt) 875 mg amoxicillin (as trihydrate) + 125 mg clavulanic acid (as potassium salt) Powder for oral liquid: 125 mg amoxicillin + 31.25 mg clavulanic acid/5 ml 250 mg amoxicillin + 62.5 mg clavulanic acid/5 ml 6. International availability – sources, of possible manufacturers and trade names Generic name Trade Names Availability Logistics Imipenem / Multiple, include: Primaxin, Widely available from Both medicines are intended for cilastatin Anipen, Cilapenem, Imenam, multiple manufacturers parenteral use. They are available as a Imiclast, Imipen, Penam, Tienam powder for reconstitution and administered via a central intravenous line Meropenem Multiple, include: Merrem, Widely available from or port-a-cath. They must be given with Meronem, Meropen multiple manufacturers clavulanic acid in order to be effective in the treatment of MDR-TB Amoxicillin and Multiple, include: Augmentin, Widely available from Clavulanic acid is the active component, clavulanic acid Amoclan; Amoxi-Clav; multiple manufacturers but all available formulations are Apo-Amoxi-Clav; Clavulin; combined with amoxicillin. The Novo-Clavamoxin, Acarbixin preparation being recommended for Aclam, Addex, Ambilan inclusion is therefore Amx-Clv, that is given as along with every dose of Imp-Cln or Mpm. Amx-Clv is inexpensive, available as tablets or syrup, with no special storage or administration needs. The reconstituted suspension can be kept refrigerated for up to 7 days following which it should be discarded 7. Whether listing is requested as an individual medicine or as an example of a therapeutic group The application for all three medications is for their inclusion as individual medicines without a square box symbol. These medications belong to the Beta-lactam class of antibiotics, which includes several other agents that are not effective against MDR/RR-TB and XDR-TB. 8. Information supporting the public health relevance (epidemiological information on disease burden, assessment of current use, target population) It is estimated that 558,000 new MDR/RR-TB cases emerged in the world in 2017 and 230,000 patients died of this form of TB(4). Between 25,000 and 32,000 children are estimated to develop MDR-TB each year(7). Many of these cases go undetected and are not placed on appropriate treatment, increasing the risk that they die and continue to transmit drug-resistant strains to others in the community. In 2017, countries reported that about 139,000 patients started MDR-TB treatment worldwide. The effectiveness of these efforts varies considerably, and data reported for patient outcomes in recent years show that only about half the MDR/RR-TB patients complete their treatment successfully. Among patients with XDR-TB the likelihood of successful outcomes is even lower. Patients who are not cured - often because their treatment fails or is interrupted - risk persistent disease or death. Given these low levels of treatment success, all efforts must be made to ensure that effective medications to treat drug-resistant TB become more widely available to the patients who need them, particularly in low resource settings which carry the largest burden of MDR/RR-TB(4). The most recent data analysis conducted for the 2018 WHO MDR-TB treatment guidelines revision attests to the effectiveness of the carbapenems - Imp-Cln and Mpm - in patients in whom other agents cannot be used to compose an adequate regimen, such as those with strains resistant to fluoroquinolones or who develop drug intolerance (see GRADE summary of evidence tables in Annex 2 from (3)). The reason why the carbapenems place so low in the priority listing of choice in longer regimens is that they need to be administered parenterally (Table 1). The two carbapenems need to be given with Amx-Clv. The inclusion of all three agents in the forthcoming EML would promote their increased use by countries in such situations and can have a life-saving role. 9. Treatment details (dosage regimen, duration; reference to existing WHO and other clinical guidelines; need for special diagnostics, treatment or monitoring facilities and skills) The three medications have a particular role in the composition of longer treatment regimens for patients with MDR/RR-TB, particularly those who have additional resistance or intolerance to one or more of the agents in Groups A and B. A typical MDR-TB regimen starts with a combination of at least 4 TB medicine drugs considered to be effective, primarily from Groups A and B (Table 1). In such a case the regimen is strengthened by Group C agents.